08 Sierra Denali HVAC Control

[beasleyiv]

I replaced the HVAC control module for cosmetic reasons. Ever since, the system loses it's mind in regards to directed airflow. Most of the time it ends up seemingly not coming out anywhere, even with the fan blowing. You can hear the air just bouncing around inside the ducts.

 

A reset of the system and calibration (after pulling fuses) fixes it for a short time. I've seen on the net that perhaps when replacing the HVAC control module that it needs to be programmed. Can you confirm? I have no DTCs set (at least that my cheap scanner can see).

 

Thanks!

[GMC Tech]

Yes. According to GM service information the replacement HVAC control module must be programmed after replacement.